The present invention relates to folding and/or unfolding circuits of a video signal in a video recording/reproducing apparatus which employs a frequency folding technique for recording a video signal of a full bandwidth on a recording medium, and more particularly to folding and/or unfolding circuits of a video signal, wherein, in order to decrease crosstalk between channels, a portion of a high-frequency luma signal band is folded on a portion of a low-frequency luma band of a limited bandwidth and the remaining high-frequency luma signal is folded on the remaining band of the low-frequency luma signal by a preset period, and then the folded video signals are unfolded into the full bandwidth.
A conventional video recording/reproducing apparatus using a frequency folding technique to record a video signal of a full bandwidth on a recording medium is described in U.S. patent application Ser. No. 07/569,029 filed by Samsung Electronics Co., Ltd. of Korea. According to the above patent application, the video signal of a full bandwidth is supplied via an encoder for generating a predetermined signal which has a low-frequency component by folding a high-frequency component signal having a decreased amplitude on the low-frequency component by means of sub-Nyquist sampling. Signals from the encoder are then recorded onto a video cassette. Here, the folded high-frequency component having decreased amplitude can be restored, and thus the video signal of the full bandwidth is reproduced.
According to an apparatus and method described in U.S. Pat. No. 4,831,463, before being passed through a bandwidth or medium which degrades resolution, a luma high-frequency component is folded on a mid-band spectrum and the original signal is then restored by unfolding the luma high-frequency component. Here, in order to provide for a narrower television signal bandwidth, the high-frequency component is processed in the mid-band spectrum by means of a comb filter and sub-Nyquist sampling.
However, the apparatuses described above have a problem in that picture quality is degraded due to crosstalk caused by the high-frequency luma component being loaded on the low-frequency band, while transmitting the folded video signal of one field recorded onto the recording medium by channels.